Heating apparatus



July 23, 1935- L. A. MEKLER HEATING APPARATUS Filed Dec. 16, 1929 2 Sheets-Sheet 1 4 July 23, 1935. 1.. A. MEKLER HEATING APPARATUS 2 Sheets-Sheet 2 Filed Dec. 16, 1929 l no 0 o \o 0 o o o o E o o o o o o o o o o o o w o o o o o o A o o o o o o o o o o o o o o o o o o N o o 90 o v R\ \W\ m m h U IR: M\ U Q a 7 0H0. or lm Ax 0H0 oHHo oi'lo 0H0 o I o r l Patented July 23, 1935 PATENT OFFICE HEATING APPARATUS- Lev A. Mekler, Chicago, Ill.. assignor to Universal Oil Products Company, Chicago, 111., a corporation of South Dakota Application December 16, 1929, Serial No. 414,270

3 Claims.

This invention relates to an improvement in furnace construction designed primarily for the heating of liquids, and more particularly where the liquids may be passed through tubes positioned in the furnace.

In the cracking of hydrocarbon oils, there is usually employed a radiant heat bank of tubes, a convection bank, and a soaking bank. The radiant heat bank is designed for the purpose of taking advantage of high heat transfer which is a characteristic of this type of heating. The

convection bank absorbs heat from thecombustion gases after they have been cooled by radiation. The soaking bank may have its heat supplied either by convection, radiation, qr both, but preferably by radiation.

The salient feature of my invention resides in a design of furnace in which the heat input to these three sections may be independently controlled and in which the soaking bank will receive the greater portion of its heat by mild radiation. While I have thus outlined some of the features of the present invention, other features will become apparent from the .following description. In the drawings, Fig. l is a diagrammatic cross-sectional elevation of one form of furnace assembly and Fig. 2 illustrates a modified construction. Referring to Fig. 1, I) represents a foundation; (2) the front wall which is protected by a. refractory interior (3),' (4) the 30 roof and rear walls which are also of suitable refractory construction; (5) represents carborundum tunnels through which a major portion of firing takes place; (6) and (l) are bridge walls, the latter serving as a partial support for the 35 roof refractory; (8) is a checkered arch between walls (6) and (l). (9) is a baflie plate extending from the front wall to the bridge wall (6).

(I0) is the shielded radiant heat tube bank; (I I) is substantially a convection bank, although receiving mild radiant heat toward the rear. (I2) is the soaking bank receiving mild radiant heat from the combustion gases. (I3) is the front air port and (I4) the rear air port. (15) is the flue gas outlet to the stack.

Preheated air is supplied to port (I 3), and if desired to port (M) by means not shown from tunnel (I 6). The cool air entering tunnel ([6) through port (I1) and by passage therethrough as shown, is preheated, thus protecting the foundation just below the carborundum radiant heat tunnels. (I8) is a damper to control the flue gas circulation from below the checker work arch into rear compartment of the furnace through port (I9). (20) are burners supplying heat to the .carborundum tunnels. (2 I) are burners supplying heat to the convection and the soaking sections of the heating coil.

By regulation of the fires maintained by means of burners (20) and (2|) and damper (l8) any desired heat condition may be maintained in each of the three sections of the heating coil thus insuring flexibility of control and conditions best suited for the purposes desired in each portion of the heating coils.

While a furnace of this type will be found very efficient for cracking of hydrocarbon oils by the so-called liquid phase method wherein the oil maintained in the tubes is substantially in the liquid phase, the installation, as shown, is especially adapted to heating requirements for vapor phase cracking conditions.

As one'method of operation, oil to be treated may be supplied to the top row of the convection bank (ll) passing out through the bottom row and into the bottom' row of the shielded radiant heat section (l0) then through the upper row of the same section and finally into the inside row of soaking section (l2) then through the outer row. Other arrangements for oil flow are intended to be within the scope of the present invention, as for instance, staggering the flow through any one or more of the tube bank sections, such as forcing fluid under heat treatment through a given bank of tubes alternately from .bottom to top, or criss-crossing the flow of such fluid through a heating zone in order to expedite the imparting of the desired degree of heat to the fluid, or-combinations of staggering with straight flow, as best suited to the conditions prevailing with the stock being treated. Figure 2 shows a modified form of furnace construction, but employing the same flexibility and substantially the same principles as those shown in Fig. 1.

I shows the refractory outline of the furnace; 2, the bridge wall; and 3, the separating wall; 4, a refractory baille plate, 5 and 6 checkered arches; I carborundum tunnels for firing; 8 and 9 dampers; l0, flue; ll, stack; I2, conduits to supply additional air to furnace, l3 and i4, burners. By providing a carborundum tunnel 1 with adjacent air tunnels I2, I am thus enabled to take advantage of the radiating action of such tunnel l to efiectively preheat the air being introduced into said furnace.

As in Fig. 1, three banks of tubes are employed, I5, being the radiant heat bank; Hi, the convection bank for preheating; l1, the convection bank for soaking. Of course, the upper two rows of tubes in banks I6 and I! will receive a certain amount of radiant energy, but they will nevertheless be substantially convection banks.

Oil will preferably flow from the bottom of bank I6 to the top, countercurrent to the flue gases, entering the radiant heat bank 15 at point l8, and emerging at point l9 to enter the top 5 tubes of bank H, which constitutes the soaking section and finally emerging from the bottom of tube bank I! to auxiliary equipment. Banks I6 and ll may be interchangeable as they are of similar construction.

It will be understood the main firing will take place through burners [3, the extent of firing being dependent upon the heat input desired in tube bank i5. In this construction no shielded radiant heat is emitted, all of the radiant energy being supplied directly from the combustion gases and heated furnace interior. Attention is also called to the fact that the radiant tube bank does not extend to the rear beyond bridge wall 2. The cooled flue gases then pass around banks I6 and i7 and being regulated by control dampers 8 and 9. If insuiiicient heating takes place therein, auxiliary burners l4 may be called upon to make up the deficiency. In any event, the heat in the banks l5, l6, and I1 may be independently controlled by burners l3 and M and by dampers 8 and 9 to obtain the conditions required in the three banks giving any desired flexibility of control. v

I claim as my invention:

1. Apparatus for heating hydrocarbon oil, comprising a furnace, a plurality of separate and independent compartments therein comprising a preheating, a primary and a soaking zone, banks of tubes in interconnected relationship disposed within each of said compartments through all of which oil passes during its course of heating withinsaid furnace, a combustion zone in communication with said preheating zone comprising means for supplying heat substantially by convection to said zone, means for introducing hot products of combustion from said combustion zone into said soaking zone to effect heating of the tubes therein by radiation and convection,

means for separately supplying heat to said primary zone substantially solely by radiation, and means for separately controlling the degreeof heat supplied to each zone.

2. Apparatus for heating hydrocarbon oil, comprising in combination a furnace, a. combustion zone therein, separate and independent heating zones therein comprisin'g a preheatingfia primary and a soaking zone, banks of interconnected tubes disposed within each of said preheating, primary and soaking zones, means in communication with said combustion zone for supplying convection heat to said preheating zone, additional means communicating with said combustion zone for supplying hot products of combustion to said soaking zone, independent heating means for supplying heat by radiation to said primary heating zone, and means for controlling the degree of heat supplied to all of said zones.

3. Apparatus for heating hydrocarbon oil, comprising a furnace, a plurality of separate and independent compartments therein comprising a preheating, a primary and. a soaking compartment, banks of interconnected tubes disposed Within each of said compartments and through all of which oil courses during its heating within said furnace, a'combustion zone communicating with said preheating zone and means for supplying hot products of combustion to said preheating zone substantially by convection, means for introducing hot products of combustion into said soaking zone from said combustion zone to effect heating of the tubes therein by convection and radiation, an independent heat source in communication with said combustion zone supplying heat to said primary compartment substantially solely by radiation, means for separately controlling the degree of heat supplied to each of said compartments, and means for preheating the air supplied to said furnace prior to its introduction into said combustion zone.

LEV A. MEKLER. 

